In recent years, the wireless communication technology using a visible light has gradually attracted widespread attention from academia and industry circles, especially with the wide use of the lightning equipment of light emitting elements like a light emitting diode (LED), while a semiconductor LED is used to achieve lightning, a feasibility study for realizing wireless communication network coverage is carried out in many related businesses. It can be seen that a communication mode of combining light communication, wireless sensor network, wireless local area network (WLAN) and power line communication system is also in discussion. However, it can be determined that the visible light communication technology will be one of optional short-range ultra wide band communication modes in the future.
As a light emitting component for high-speed light data communication, and considering the influences on human body or medical equipment, an LED is a most powerful candidate. At the same time, a semiconductor light emitting device with higher-speed response performance, for example a laser diode (LD) or a super luminescent diode (SLD) also can be used as a visible light communication device for sending the visible light carrying data information. The data rate in the light communication depends on the response speed of a light emitting device. Because of the reason, the light emitting device with higher-speed response performance attracts more attention.
The basic principle for realizing visible light LED communication is to perform a certain modulation on emitted light through data to be sent, such as pulse width modulation, pulse location/frequency modulation or pulse amplitude modulation. This modulated light energy is transmitted through a space channel and is received by a photoelectric detector (or a sensor) on a target apparatus, and after the photoelectric detector converts a light signal into an electrical signal, and after subsequent processing, data carried in the light signal is demodulated.
According to application scenarios of the visible light in the future and its special features, portable devices equipped with a camera will become more and more. Various LEDs are used as information publishing systems, and various portable/mobile terminals are served as receiving systems, which will be a simple communication mode. The topology networking transmission method among visible light communication nodes will further influence the technical development of a visible light communication system. Although the visible light communication technology has the above-mentioned advantages, a topology networking mode for various communication nodes in the visible light communication system is not proposed at present so that visible light resources cannot be effectively used.
Aiming at the above-mentioned problem, no effective solution has been provided at present.